The general acceptance of industry automation as an essential requirement for improving productivity has increased the acceptance level of the robot or manipulator apparatus as a mechanism for achieving automated industrial applications. The acceptance of robots as a useful, industrial "tool" has resulted in a market demand for a robot system exhibiting the simplified design considerations of a machine tool suitable for control by conventional computer numerical control, direct numerical control and off-line programming with language such as an Automatic Programmed Tool (APT).
High powered lasers are ideally suited to be used as a source of heat in various material processing applications which include the vaporization of materials, drilling and cutting operations. Lasers are also applicable to procedures, such as welding or surface cladding of materials, that is to say processes and procedures which require the melting of materials. Also, the temperature of solid phase materials can be varied by the use of the laser in hardening and annealing operations.
The thermal affects which are experienced by materials when exposed to the laser beam are primarily dependent on the intensity of laser energy, the absorptivity of the material, and the length of time during which the material is exposed to the laser beam. Precise control over these parameters determines the resulting change in the phase or the state of the material. Usually, when lasers are used in processes such as welding, cutting and surface treatment, the area of the workpiece to be processed is oriented in such a way that it is nearly normal to the laser beam with the beam impinging squarely on its surface. This configuration optimizes the absorptivity of the material and facilitates its heating. Generally, the laser and the workpiece are caused to move relative to each other. This relative motion can be accomplished in two ways. First, the beam can be traversed over a stationary workpiece. Second, the workpiece can be manipulated under a fixed laser beam. Typically, the former method requires that the laser beam be moved either by mounting the laser on a movable device or by directing the beam from a fixed laser to the workpiece by use of a movable optical system.
A dedicated effort has been directed to the optimization of the use of industrial manipulators and high powered lasers to provide an integrated laser robot system. U.S. patent application Ser. No. 485,076 entitled General Purpose Orthogonal Axes Manipulator System by Daniel P. Soroka et al., which is assigned to the assignee of the present invention, discloses an overhead gantry style robot with a large rectangular working envelope. This robot permits programming in Cartesian coordinates as contrasted with the more complicated polar coordinates. This gantry robot design provides a rigid manipulator that supports machine tool-type interpolation moves, high accuracy and repeatability while permitting robotic-type velocity and dexterity. The gantry design provides for an overhead X axis assembly supported by vertical structural members. The Y axis assembly extends as an arm from the X axis assembly and further supports a vertical Z axis assembly. In addition to the orthogonal X, Y and Z axes assemblies, a mounting surface on the Z axis assembly is designed to accommodate a multiple axis rotary wrist to which an appropriate end effector can be attached. This end effector can be a gripper, welding torch, or as will be described herein, a YAG laser or the delivery point of a laser delivery system.
Allowed U.S. patent application Ser. No. 460,346 which is entitled Robotic Laser Beam Delivery Apparatus by Daniel J. Plankenhorn which application is assigned to the assignee of the present invention, discloses a light beam directing apparatus which permits a reflected beam of light, such as a laser, to be directed in a path which comprises a plurality of straight segments. Each segment of the beam is associated with a segment of a robots axis in a fixed spatial relationship. The aforedescribed patent applications describe only a portion of a total system that is utilized according to this invention to provide a complete work cell. The present invention describes several important items which when used in combination with the gantry-type robot and laser beam delivery system provides a complete work cell.
It is, therefore, an object of this invention to provide a robot-laser system which allows for a new methodology which can overcome many of the productivity-limiting problems of present techniques by means of the flexibility, versatility and adaptability of the robot-laser system of this invention.
It is another object of this invention to provide a robot-laser system in a work cell configuration which includes unique safety features which enclose the working envelope of the industrial manipulator and provide a safety fence surrounding the complete system.
It is a further object of this invention to provide an air filter and dryer mechanism by which dust and condensation on the reflective surfaces of the laser delivery system are eliminated and a desired environment within the laser delivery system is established.
It is yet another object of this invention to provide an exhaust system by which toxic fumes emitted during the laser cutting and cladding process are removed from the work area.
It is still another object of this invention to provide an extensive range of process dependent peripheral devices which can be located within the working envelope of the industrial manipulator.